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Re: _Discover_ article
On Mon, 25 Nov 1996, Stephen Faust wrote:
> On Sun, 24 Nov 1996, Dave L. Hardenbrook wrote:
> > Has anyone seen the article in the December _Discover_ magazine
> > about Tomasz Owerkowicz using nasal cavities as refutation of
> > hot-blooded dinos and confimation of the mass homeothermy theory?
> > He says that dinosaurs lacked turbinates, special organs in the
> > nasal cavity of warm-blooded animals. He also thinks that the nasal
> > cavities themselves were too small to allow dinosaurs to inhale a
> > sufficient quantity of oxygen to sustain a warm-blooded animal.
> > Anyone care to comment on this thesis?
> You might want to email your thoughts and speculations re:hot vs cold -
> blooded dinos to Hillenius at the College of Charleston, SC.Thats
> email@example.com.I have read the article and studied under him.He
> found that dinosaurs studied, including several therapods, had neither
> turbinates or projections within the nasal cavity that might have
> supported turbinates.The nasal cavities of dinosaurs studied were
> similar to those of crocodiles, narrow and much smaller than cavities
> seen in endotherms.
> Tomasz found that stress produced changes in reptilian bone that would
> lead one to conclude the bone came from an endotherm.
> Reptilian physiology would not have precluded the level of activity
> depicted in "Jurrasic Park". The only inaccuracy in the film: dinobreath
> would not have misted refrigerator glass.
Before GSP goes and growls at us all...
GSP did a poster at the SVP on the RTs (acronymania...) showing how the
relatively large size of the heads of many dinosaurs makes the nasal
passages look smaller. I think the drawing showed that the nasal passages
of a mid-sized theropod were about the same size as those of a similarly
sized elephant-bird. Relative to the skull, of course, the nasal passages
of a pinheaded elephant bird were *much* larger than those of a big-headed
Also, GSP notes that they may have been cartilagenous in many cases
and so would not show up. Bone textures also seem to be far more
complex and difficult to read than anyone had thought they would be.
Finally, a full-body insulatory coat on the theropod Sinosauropteryx
is very good evidence that it was fully endothermic (endothermy
naturally being a diverse range of physiologies encompassing extremes
such as the lukewarm monotremes and the hot-blooded songbirds) and it is
simplest just to assume that this animal was warm-blooded. This, and the
fact that close dinosaurian relatives, the pterosaurs also appear to have
had insulation, further supports the possibility that dinosaurs as a
group may have been endotherms. Brooding behavior in oviraptor, high
degrees of aerobic activity, presence at very high latitudes, and high
growth rates are further substantiating evidence of endothermy in the